This invention relates generally to processor-based systems and particularly to systems including two separate processor systems that communicate with one another.
In many wireless systems, a baseband processor is available to handle communication tasks. A multimedia processor is generally available for the wealth of non-communication-based tasks. For example, in cellular telephones, the baseband processor may be responsible for implementing the relevant wireless protocol. Conversely, the multimedia processor may be responsible for controlling the display, providing games, and implementing address book and calendar features and the like.
Thus, it is convenient in many wireless systems to provide two processors that operate as intercommunicating systems. That is, each processor system communicates with the other processor system. The processor systems may be separately integrated or commonly integrated on the same chip.
Direct memory access or DMA forms a second data channel between peripherals and main memory through which a peripheral can directly access the main memory without the help of the processor to read or write data. DMA may be implemented by a DMA controller.
Existing DMA controllers are primarily concerned with the internal data flows of a particular process or processor. Streaming data flows between different processors in the same processor-based system add additional complexities that may lead to flow bottlenecks and inefficient use of processor resources. Each DMA controller, in a multi-processor system, may be focused on its associated processor, resulting in too many interrupts to each processor.
Thus, there is a need, in multi-processor systems, to facilitate DMA operations.